<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="test3_1.js"></script>
</head>
<body>
    <input type="button" value="按钮" onclick="alert('按钮被点击了')">
    <!-- <script>
        alert('页面加载完成');      
    </script> -->
</body>
</html>